The neuroscience of chronic pain

The neuroscience of chronic pain

Presented by: Professor Lorimer Moseley

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Spencer Howsen: Professor Lorimer Moseley, welcome to the podcast.

Professor Lorimer Moseley: Thank you very much. It's a pleasure to be here.

Spencer Howsen: Well, first of all, what is pain? I'm sure you could give me 20,000 word thesis or more, but what do you mean by pain? What should we understand pain to mean?

Professor Lorimer Moseley: That's a clanger because what we mean by pain I guess is what it means to us. So I can tell you everything about my pain. You could tell me everything about yours. From a scientific perspective, the current way of understanding pain is that it is a feeling that your brain produces and it will produce that if all of the data available to it, and that's just, I guess, a scientific way of saying if everything in your world at that moment and in your body at that moment suggests that the very best thing for you would be to protect that body part, then you will have pain.

Professor Lorimer Moseley: So we think about pain as a protective feeling, felt somewhere in the body, that urges us to protect that body part. So it's actually really different to the common understanding of pain. So the scientific understanding of pain has shifted a lot in the last 30 years. In fact, it's been transformed. Maybe 50 years. Actually in the last 50 years we have shifted from an understanding of pain as a sign that there is damage, to pain being a fundamental process by which we stay alive and we keep our tissues safe. So the transformation is in the shift from pain detecting something's wrong and telling you, "Oh, you've done something", to pain being a protective thing that says, "Hang on, you're getting too close to damaging something." In actual fact, even though we have these experiences where, oh, you put a Thumbtack in your thumb and you pierce the skin and it really hurts, so you have damage and you have pain, the illusion is that the damage is causing the pain.

Professor Lorimer Moseley: What's really happening, all our experiments and these are volumes and volumes of research articles tell us that you have pain so that you now stop that thumb from being exposed to any danger because it's got to heal and you have it immediately. But what people will notice, and I don't recommend anyone does this experiment, right? But what people will notice is if they do start to push a Thumbtack into their skin, they will nearly always hurt. They get pain before they damage skin. I'll say that again because I think it's really powerful. You get pain before you damage skin. In fact the pain is at its absolute most that nanosecond before your pierce the skin, right? People can do all sorts of mind tricks so that they can do these things without pain, but also we can do tricks on people where we make them think they've got something sharp coming into their skin.

Professor Lorimer Moseley: If we can do that in a really compelling way, we'll have exactly the same feelings as if we were doing it. Right? So these sort of findings tell us, hang on, this old idea that pain was something that is sort of detected or generated in the tissues of the body and sent to the brain, there's just too much evidence to say it doesn't actually work like that. It feels like it works like that, and we definitely have pain most of the time that we're injured, but we also have pain a lot more often not associated with injury, and we can have injury not associated with pain. In fact, just done this talk at this conference obviously, and I'll put up this slide, getting across the idea that for an injury to be pain free, it normally has to be catastrophic.

Professor Lorimer Moseley: I'll say that again because that's also a mind mess, right? For an injury to be pain free, it's got to be catastrophic level. Minor injuries are more painful than catastrophic injuries. Substantial injuries are more painful than catastrophic injuries. The catastrophic injuries are usually pain-free until you're safe. Then you have a lot of pain because the system is working so hard to protect those tissues while they heal. A classic example, people at war who have a life-threatening catastrophic injury who are pain-free until they're safely behind lines at the hospital where their life is safe and then their brain goes onto the next most important thing. Ah, protect your shoulder while you heal, for example.

Spencer Howsen: Okay, so first a couple of observations. Firstly, I bet everyone is playing with their thumb right now and imagining that a tack just went into it. Secondly, you're so right with that tack, even before it's pierced, you feel the pain, don't you, so there's no reason for the pain.

Professor Lorimer Moseley: Ah. Can I respond to that? Because even before it pierces you feel pain, absolutely. I agree with what you said, but your implication was also there is no reason for pain. There's every reason for pain because it's the pain that stops you piercing the skin. Unless you really intent on doing it. That's the thing that says I'll back off now. Right? If we didn't have pain, then you'd keep getting injured and in fact there is a genetic deformity where the danger detectors in your skin don't develop properly. They're missing a critical gene. Those people usually die young because their system doesn't learn to make pain in order to stop tissue damage. Sorry to pick you up on that.

Spencer Howsen: No, no, no, absolutely. So pain fundamentally, biologically is a good thing, but I'm sure that listeners can tell where we're heading with all this, which is in terms of the impact of pain on workers, employers and organizations. If you can separate ... if you're saying that the pain is created in the brain, then it's possible to control the pain, especially if you're talking about a long-term pain from something that's not actually physically happening, right?

Professor Lorimer Moseley: In broad terms, yes. I think that the challenge is immense and I don't personally use that sort of phrasing of, right, well, if it's produced by the brain, we should be able to control it. Because for me, that presents this horrible dichotomy within a unified human. It is us making the pain and it is us trying to control the thing we're making. So it's a bit counter. I think we're on the same page if we think about what we're wanting to do, but what we do know from our research and from my clinical experience, I've dealt with a lot of people with persistent pain for whom their pain is not serving a useful protective function anymore. So they're highly disabled, highly distressed, that their body is actually safe. So this is a horrible situation to be in.

Professor Lorimer Moseley: Rather than talk about the idea of anything that might imply, "Well this is all in your head", I don't believe that. What I believe is that the longer we have pain, the more protective the pain system becomes. So actually the safer our tissue becomes in some ways with the catch, and that is that when you become sufficiently over protected that that pain prevents us from doing the very things our tissues need to be healthy and to recover and to be well and strong. Then they are becoming sort of more in danger, but their pain is still trying to keep them safe.

Spencer Howsen: Can you give an example of that where the pain is stopping you doing what you need to do to recover?

Professor Lorimer Moseley: Yeah. The very common example of that is persistent back pain. I think the fact that we as a field in the health healthcare field and the wider community hasn't moved on from that understanding of pain being a damage marker. The fact that we haven't moved on to a contemporary understanding of pain being a protector is responsible for a lot of these situations where people have persisting horrible back pain and it feels just like they're broken or they're about to break. But actually ... Sorry. That stops them from putting load through the tissues. Right. So that limits their movement. It limits the amount of time they spend active. It limits the amount of time they can stay in one location. It limits the amount of force they prepared to put through their back because it hurts so much. It really hurts. So you have to really emphasise that they're not making this up. This is genuine, a biological adaptation, but the very thing their back needs to get well and also they need as a human to stay well to prevent the development of secondary problems that are also problematic.

Professor Lorimer Moseley: Cardiovascular disease, stroke risk, cancer risk. All of these things are associated with persistent pain and the best way to limit that impact and the best way to manage these persistent pain problems is through active based things. Loading the tissue and it doesn't have to be much. Any loading is good loading and the general message that we want people to understand, once they've been cleared, they have to be cleared, but you normally have to be cleared once of anything catastrophic or sinister or true risk. We've got the tests to detect that and to mark it. Once they've been cleared, then they are safe to move. Now I'm not saying they're safe to go and run a marathon because they're not. They will either flare them up and be in so much pain and wind up their nervous system and immune system for a long time.

Professor Lorimer Moseley: Or if they've got a really strong conviction that they should go and do a marathon, then they could do damage because they're out of touch. They're out of training, they are not as strong, they're not all those sort of things. So the most common example is persistent back pain, where a little bit of movement is the best thing they could do, but even a little bit of movement hurts so they don't do it, which is a reasonable decision. So the real push of the work that people like me are doing now is to find better ways of empowering people with pain, of enabling them, informing them and getting them an understanding that they have a big protective buffer. So it feels like they're not at all safe, but actually they are very safe. It's a challenge for us to get across that and to get across that with an understanding of the lived experience of pain.

Spencer Howsen: So how much is that up to doctors, a person's doctor, and how much is up to the person and how much is up to the workplace to empower people at that point?

Professor Lorimer Moseley: I love that question, and a part of me was hoping you'd keep going. You'd keep going. So how much of it is up to the general media? How much of it is up to our school teachers? How much of it is up to the local football clubs? How much is up to the CEOs of our companies? How much is up to the HR departments? How much is up to the boss? How much is up to us as someone's line manager? I would say in answer to that, we need everyone. I think what the data clearly show is that guidelines, the release of guidelines for clinicians to follow, haven't had the desired effect. They are important, but they haven't had the desired effect.

Professor Lorimer Moseley: The economic models though, the funding models the health professionals have for treatment don't encourage best practice care. One of the most remarkable things in this country in many jurisdictions is that in aged care facilities, the very things that people need to do, that a physiotherapist could help them with for example, there's no funding for that. But the things that we now know are not helpful, there is funding for. So add to the list how much of that is up to the people who decide funding mechanisms? So really, I mean, this is where I'm really engaged at the moment. I mean, I'm a scientist, I'm an educator, I'm a clinician and what I've found myself being is an advocate, I guess, to say everyone needs to understand this. From primary school teachers, parents, high school teachers, university lecturers for people doing health professions, doctors, physios, OTs, EPs, psychologists, policymakers, big companies with money to put ads on television, return to work.

Professor Lorimer Moseley: Everyone needs to understand this so that we can have this mass shift so that when anyone injures themselves, they appreciate that their system will be working to keep them safe and their system is very good at that. Sure, they might need some intervention. Absolutely. But their system has great inbuilt capacity to protect them while they recover and retrain their tissues. A thinking experiment that I put forward in this talk I've just done was to all the clinicians in the room. Just imagine that your patients were turning up asking for high value care, asking for best practice. Not asking for outdated practice by outdated scientific models, and your first challenge is to win them around to a counterintuitive approach. Wouldn't it be great if the approach was intuitive because it's intuitive to the people who understand modern pain science. It's not intuitive to the people who don't.

Spencer Howsen: So it does ... We'll take what you call a pain revolution. Everyone has to be on board and you can see from the example you just gave there how that's important. If you're the patient, you need to understand this new way of thinking as well as the clinician and everyone else involved.

Professor Lorimer Moseley: Yeah, I believe you do. Actually, some people who become patients, they actually understand and apply this way of thinking for some conditions but don't for others. My favourite example is an ankle sprain. Most people who sprain their ankle understand that it will really hurt while it's healing and they can push it a little bit more every day and they test it. They get out of bed and I test it and they think, "Oh, I might've over done it today. It's a bit sore", but usually they don't conclude, "I've re-damaged it."

Professor Lorimer Moseley: However, very similar tissue injury in an injury to the outside of the intervertebral disc, let's say.

Spencer Howsen: Where's that?

Professor Lorimer Moseley: Intervertebral disc, so in between the two vertebra is this amazing structure that I call a LAFT, which stands for living adaptable force transducer because it manages to convert all the loads on your back into tension on ligaments and the ligaments ... so this is the same structure as the ligaments on the outside of your ankle. It's just that there's heaps of them in every single disc or LAFT. There's heaps and heaps of this ligament. This stuff is so strong and it's so bound to the vertebra in [inaudible 00:15:29]. But when we hurt our back, we don't address it usually likely would an ankle sprain. We are at risk immediately of seeing a healthcare professional who's not informed, who then feeds into the sense of risk and changes your direction and you get a scan and because I'm 49 the scan shows that my back no longer looks like it did when I was 15 because I'm adapting and things are changing and it's usually becoming stronger and slightly less mobile, which reflects my life demands.

Professor Lorimer Moseley: But the report comes in and says, "Oh, you've got degenerative changes. You've got bony outgrowth here and there". Me, in this particular area of knowledge, I'm highly informed and I know why that bone grew because it's adapting to load. But 99% of people who are not in that space will think, "Oh, no, I've got this deformity. I've got a degenerative disease", and that's evidence for your brain that you should protect. When you get evidence for your brain that you should protect, it makes pain. So we feed into the problem with this.

Spencer Howsen: Okay. So the example you gave there of people with a sprained ankle pushing every day to see how much more they can ... pushing through the pain suggests that's a sort of physical thing that people are doing. Can we just go back to the word that you picked me up on where I talked about controlling your own brain? Is retrain the brain a better word than control the brain to actually tell the brain in a way that's not a physical way like pushing that ankle, but another way? Is there other ways of training the brain to say there's no pain there or there doesn't need to be pain there?

Professor Lorimer Moseley: Yeah, great point. So I'm actually more comfortable with the idea of controlling the brain because there are meditation things [inaudible 00:17:23] a volitional and involuntary thing you can do that change what the brain's doing and learning how to attend to different things and all sorts of things. Controlling the pain is for me a different concept because the pain is not an entity to be controlled, right? Pain is something that we produce. I love the idea of training the pain system and training the brain is part of that. I've moved away from the idea of just focusing on the brain actually in the last 10 years. If this was 10 years ago, I would've said, "Yeah, retrain the brain. The brain does everything, yada, yada, yada." We've learnt a lot in the last 10 years in the scientific field about the importance of all of our systems. Our nervous system, obviously. Our immune system. Our endocrine system. Our sympathetic nervous system.

Professor Lorimer Moseley: All of our systems contribute to what I would call the pain system. In the same way all of our systems contribute to the fatigue system or the anxiety system, the fear system, the feeling stiff system. All these sort of conscious feelings or moods and pain I would describe as a feeling. So your question was can you retrain the pain system? That wasn't your question, I've reworded it. Can you retrain the pain system? Yeah, you can. Absolutely. When you were talking about the ankle, we talked about each day you push to see if you can do a little bit more. I like to tell people you can push into the pain. I don't say you push through the pain because the pain is serving a protective function.

Professor Lorimer Moseley: So you know that after an injury you have a bigger protective buffer so you're safer to push into pain a bit more. If you've got no injury at all and you push into and try and push through the pain, you will injure. If you've got an injury and you've got inflammation which changes everything, then pushing into the pain, you're very unlikely to cause an injury unless you do it really, really quickly and violently. Or you're some kind of psychological freak and go and run a marathon with an inflamed foot or something. So most of us humans pushing into the pain is the way to go. Not brutal. There's one rule that is used by a lot of people called the take two rule and that is push into something to take your current pain up by two points on a 10 point scale and then back.

Professor Lorimer Moseley: Now I don't like those formula ideas. I'd much rather people understood why this is safe and what's different, how they should respond when the pain changes, those sorts of things. But your question about retraining the pain system. Absolutely. We now know you can, and the first step to that is understanding that the pain system's over-protective setting at the moment is the problem and identifying those things. So we call the things that are setting off the pain system DIMs, danger in me, and they can come from everywhere. They can come from the tissues of your body. They can come from a general inflammatory setting. Some people are a bit more inflammatory than other people genetically. Some people are a bit more inflammatory than other people because they eat a lot of inflammatory foods or they don't get enough sleep or they don't get enough exercise. All these sort of general things. Right?

Professor Lorimer Moseley: What we know is that in those states, the more overprotective the pain system gets, the more the range of things that will take that protective meter, if you like, protective setting up and will produce more pain. So the first step is education. Understanding. We're doing a lot of work on that and it's hard, but when people get it, their life is transformed. We need to be better at helping them get it. Then they reengage with the sort of things that they might've heard of before but didn't make sense or have been implemented badly by the health provider and reengaging with active strategies. Now those active strategies might be physically active or they might be what we would call cognitively active. Right? So those sort of things are more the mindfulness and learning.

Professor Lorimer Moseley: Learn something new. Even better, learn something new about pain. Yeah. So really you've got to work at this. Learning is not an easy thing. It's an active process or they can be physically active things. Still one of the best treatments for chronic low back pain is walking. That's not for everyone, but we, like to say, "Okay, you don't have to go and get into a gym and go nuts, but get some load through those tissues of your back. Get your muscles contracting. Get your joints moving a little bit and little by little things will progress." So you retrain the pain system by exposing your pain system to all of those things that increase the protection setting, but in small amounts and gradually increasing amounts. So I guess to reiterate that we have education and understanding is the key. It's not like we can just say, "Here, read this." You got to you got to learn it. So learning and understanding.

Professor Lorimer Moseley: Identifying all of the cues that are contributing evidence of danger in you, and look everywhere for those things. We have this list for people. Things that you do, that's easy. Things that you think, that's bit a confronting. Things that you feel, people in your life, places you go, the state of your body, all these things. So it starts to get a bigger list and you have to be courageous sometimes. Yeah. You have to move away from this idea that, let's say, back pain is only about the back. There's no human in existence for whom back pain is only about the back, right? Because exactly the same person with back pain standing there at work, having picked up a too heavy box, if you put them in front of lines, they don't have back pain. They escape the line. They're in fear.

Professor Lorimer Moseley: So it's very contextual. So every single pain experience relies on the brain evaluating everything at that moment. I don't want anyone listening to this thing for one second that I'm saying pain is all in your head, don't worry about it. I'm not saying that at all. But what I am saying is that everything matters. So education, learning, identifying the things that are triggering it or modulating it and remove all the things you can. Some things you can't remove. So then you have to find all the things that tell the system to back off. Tell the system, "No, you're actually a bit safe," and those sort of things you look in the same places. Things that you do that that make you feel safe. People you're with, places you go.

Professor Lorimer Moseley: All these sorts of other ... Things you think things you say, things you hear and when you know you have to expose to a DIM, right, and the DIM might be, "I know I have to go and pick up the kids from school", right? Can you couple with that some SIMs? Well, don't just go mindlessly there worried about this situation. Go knowing that you're safe. You're not going to damage tissue, and why don't you listen to your favourite music on the way and appreciate the beautiful day. Or if it's raining, it's a horrible day, listen to your favorited music and just think about how good that water is for our farmers. Now this might sound really almost platitudistic, if that's a word, like a platitude. But the science tells us in a very compelling way that everything matters.

Professor Lorimer Moseley: So identify, remove DIMs, find SIMs, and then take on the journey. So once you're re-engaging with things, finding the things that work for you, take on a slow journey of recovery. It's slow, and there's no quick fixes that we know of anywhere for this. The journey is slow, but if you stick at it and you remember the principles of your own bioplasticity in your own system, then we have the data now to say recovery is back on the table. It's a possibility, but it's a long journey that will transform you as a person.

Spencer Howsen: I want to pick you up on one of those DIMs. Well, they're all in both categories potentially, but one which was people. People that you interact with, the people you surround yourself with, they can actually have an impact positively and negatively on your pain.

Professor Lorimer Moseley: Yeah. One of the characteristics of an over protective pain system is that it can be set off by your social environment. So by the people you're with. An over protective pain system. A normally protective pain system wouldn't be, right? But an overprotective pain system might be. So we think, well, who makes you feel safe? Hang around with them. I mentioned you've done one of these with Donna who spoke before I did at this conference and one thing that she mentioned and she said that this was data. I have no reason to not believe that. I haven't seen the data. I don't know what the study was, but it was something like you are the average of your five closest relationships or something like that and that in principle makes a lot of sense.

Professor Lorimer Moseley: If there are people ... Once you've identified, actually. This is the power of this understanding, that if you identify that, "Well, it's this person. I don't feel safe around that person" and you identify then, "And actually my shoulder hurts a bit more around that person." Once you've identified that and you have a biologically sensible explanation for it, then it reduces its power because your brain starts to think, "Well, I don't need to protect my shoulder around that person. I need to protect me", or "I need to have some strategy to engage with that person", or "I need to have this out with this person", or "I need some coaching on how to integrate this into my work life" or whatever. But the relationship with pain fades. We know that from research, that identification of these cues, people, places, things you hear, things you say, things you do, identifying them as a DIM, just the process of identifying it, can often take some of the power out of it.

Spencer Howsen: Okay, so finally to wrap this all up in a bow. Just talk to me for a moment about employers who will be listening to this not wanting to lose workers permanently or temporarily and wanting to see staff come back to work and in both groups people affected by pain. What can employers do to reduce, I suppose, the lost hours, which in itself is a positive then for the staff involved?

Professor Lorimer Moseley: Yeah, sure. So if I take that example and put a bit more precision onto it and say, "What can the employer do when someone is injured at work?" I think what the employer can do is act fast to understand what happened. Understand the experience of that person and exclude the possibility of something that needs extra attention and good health care professionals can do that. If the target is exclude catastrophe and need for further intervention and then resource this individual with the skills to master their recovery.

Professor Lorimer Moseley: So the employer who has control or has influence over what happens after an injury I think should be all about care, respect, solve the problem and assist the worker's recovery. One way that that has manifested in South Australia, and it looks like as well in Queensland, is the shift. The whole organisation in South Australia has changed from WorkCover to ReturnToWorkSA. If you do that in a more global way, if I had control, I'd say recovery. That's what we're about. So what do you need? Let's help you recover. So the employer, on a systemic level, on a policy level, can do that. On a line manager level, the understanding and respect of your line manager is an important contributor and in some studies has been identified as a measurable risk factor for poor recovery. Low satisfaction, low feeling like you're being seen as legitimate in the eyes of your line manager. There are a range of studies where little things like the line manager just ringing them up or even someone higher up the chain.

Professor Lorimer Moseley: Ring them up on day three, "I heard you hurt your back there. We're on top of it. Is there anything you need from us at the moment you're not getting?" Little studies. Or they're big studies with little things have proven helpful in improving recovery. So the other thought I had when you asked that question was maybe just the principles that came out at the end of Donald's talk actually feed into this. That we remember that we have the opportunity in our engagements with someone in pain and actually someone, full stop. Let's say we're talking about someone in pain. We have the opportunity to deliver DIMs or deliver SIMs and delivery of SIMs should help recovery. Right?

Professor Lorimer Moseley: Because the system has the capacity to protect itself. It would be bad for a boss to say, "Oh, I know everything's safe. I understand backs," when they clearly don't. But also, employers, and this goes back to a system thing. You need to have relationships with current thinking health professionals. You need to have access to someone who can teach your staff contemporary pain science and evidence based practice. There are people out there who do that and there are probably still more people out there who are not like that. So you choose carefully and I think that will make a difference.

Spencer Howsen: Thanks for being on the podcast today.

Professor Lorimer Moseley: Real pleasure. Thanks for letting me just ramble. That was great. Thanks for having me.

Spencer Howsen: It wasn't too painful for us. See what I did there.

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